Animooted barrel roll from the original Star Fox
The barrel roll is an aerial combat maneuver in which a fighter plane spins clockwise or counterclockwise while still flying forward. By 2006, the line do a barrel roll, a line that Peppy frequently shouts in the game Star Fox 64, is ubiquitous on /b/. In the game, your fighter is invincible while barrel rolling.
Do a barrel roll, like stick it in her pooper, is often used as a stock reply when someone asks for advice (usually with the tagline "What do I do, /b/?") on /b/.
Barrel roll from Star Fox 64,
complete with Peppy's incredibly annoying line.
Often used during phone-in raids on TomGreen.com Most famously used by Xenon.
Ironically, the "barrel roll" depicted in the game is actually an aileron roll.